At what colleges can I study fashion design, merchandising, and/or retail management?

It could be any college. I would prefer a campus near Illinois or New York city. But remember it could be any college in the U.S.

Academy of Art, American Intercontinental university, The Art Institute and some other colleges can help you in this regard. I'm giving you a link where you can find more about the possibilities and also apply for online fashion design degree.

Best of luck!